Reply to Objection 3: Mission, meaning procession from the sender, includes the signification of a notion, not of a special notion, but in general; thus "to be from another" is common to two of the notions.
Whether it is fitting for the Son to be sent invisibly?
Objection 1: It would seem that it is not fitting for the Son to be sent invisibly. For invisible mission of the divine person is according to the gift of grace. But all gifts of grace belong to the Holy Ghost, according to 1 Cor. 12:11 : "One and the same Spirit worketh all things." Therefore only the Holy Ghost is sent invisibly.
Objection 2: Further, the mission of the divine person is according to sanctifying grace. But the gifts belonging to the perfection of the intellect are not gifts of sanctifying grace, since they can be held without the gift of charity, according to 1 Cor. 13:2 : "If I should have prophecy, and should know all mysteries, and all knowledge, and if I should have all faith so that I could move mountains, and have not charity, I am nothing." Therefore, since the Son proceeds as the word of the intellect, it seems unfitting for Him to be sent invisibly.
Objection 3: Further, the mission of the divine person is a procession, as expounded above (AA[1],4). But the procession of the Son and of the Holy Ghost differ from each other. Therefore they are distinct missions if both are sent; and then one of them would be superfluous, since one would suffice for the creature's sanctification.
On the contrary, It is said of divine Wisdom ( Wis. 9:10 ): "Send her from heaven to Thy Saints, and from the seat of Thy greatness."
I answer that, The whole Trinity dwells in the mind by sanctifying grace, according to Jn. 14:23 : "We will come to him, and will make Our abode with him." But that a divine person be sent to anyone by invisible grace signifies both that this person dwells in a new way within him and that He has His origin from another. Hence, since both to the Son and to the Holy Ghost it belongs to dwell in the soul by grace, and to be from another, it therefore belongs to both of them to be invisibly sent. As to the Father, though He dwells in us by grace, still it does not belong to Him to be from another, and consequently He is not sent.
Reply to Objection 1: Although all the gifts, considered as such, are attributed to the Holy Ghost, forasmuch as He is by His nature the first Gift, since He is Love, as stated above (Q[38], A[1]), some gifts nevertheless, by reason of their own particular nature, are appropriated in a certain way to the Son, those, namely, which belong to the intellect, and in respect of which we speak of the mission of the Son. Hence Augustine says (De Trin. iv, 20) that "The Son is sent to anyone invisibly, whenever He is known and perceived by anyone."
Reply to Objection 2: The soul is made like to God by grace. Hence for a divine person to be sent to anyone by grace, there must needs be a likening of the soul to the divine person Who is sent, by some gift of grace. Because the Holy Ghost is Love, the soul is assimilated to the Holy Ghost by the gift of charity: hence the mission of the Holy Ghost is according to the mode of charity. Whereas the Son is the Word, not any sort of word, but one Who breathes forth Love. Hence Augustine says (De Trin. ix 10): "The Word we speak of is knowledge with love." Thus the Son is sent not in accordance with every and any kind of intellectual perfection, but according to the intellectual illumination, which breaks forth into the affection of love, as is said ( Jn. 6:45 ): "Everyone that hath heard from the Father and hath learned, cometh to Me," and ( Ps. 38:4 ): "In my meditation a fire shall flame forth." Thus Augustine plainly says (De Trin. iv, 20): "The Son is sent, whenever He is known and perceived by anyone." Now perception implies a certain experimental knowledge; and this is properly called wisdom [sapientia], as it were a sweet knowledge [sapida scientia], according to Ecclus. 6:23 : "The wisdom of doctrine is according to her name."
Reply to Objection 3: Since mission implies the origin of the person Who is sent, and His indwelling by grace, as above explained (A[1]), if we speak of mission according to origin, in this sense the Son's mission is distinguished from the mission of the Holy Ghost, as generation is distinguished from procession. If we consider mission as regards the effect of grace, in this sense the two missions are united in the root which is grace, but are distinguished in the effects of grace, which consist in the illumination of the intellect and the kindling of the affection. Thus it is manifest that one mission cannot be without the other, because neither takes place without sanctifying grace, nor is one person separated from the other.
Whether the invisible mission is to all who participate grace?
Objection 1: It would seem that the invisible mission is not to all who participate grace. For the Fathers of the Old Testament had their share of grace. Yet to them was made no invisible mission; for it is said ( Jn. 7:39 ): "The Spirit was not yet given, because Jesus was not yet glorified." Therefore the invisible mission is not to all partakers in grace.
Objection 2: Further, progress in virtue is only by grace. But the invisible mission is not according to progress in virtue; because progress in virtue is continuous, since charity ever increases or decreases; and thus the mission would be continuous. Therefore the invisible mission is not to all who share in grace.
Objection 3: Further, Christ and the blessed have fullness of grace. But mission is not to them, for mission implies distance, whereas Christ, as man, and all the blessed are perfectly united to God. Therefore the invisible mission is not to all sharers in grace.
Objection 4: Further, the Sacraments of the New Law contain grace, and it is not said that the invisible mission is sent to them. Therefore the invisible mission is not to all that have grace.
On the contrary, According to Augustine (De Trin. iii, 4; xv, 27), the invisible mission is for the creature's sanctification. Now every creature that has grace is sanctified. Therefore the invisible mission is to every such creature.
I answer that, As above stated (AA[3],4,5), mission in its very meaning implies that he who is sent either begins to exist where he was not before, as occurs to creatures; or begins to exist where he was before, but in a new way, in which sense mission is ascribed to the divine persons. Thus, mission as regards the one to whom it is sent implies two things, the indwelling of grace, and a certain renewal by grace. Thus the invisible mission is sent to all in whom are to be found these two conditions.
Reply to Objection 1: The invisible mission was directed to the Old Testament Fathers, as appears from what Augustine says (De Trin. iv, 20), that the invisible mission of the Son "is in man and with men. This was done in former times with the Fathers and the Prophets." Thus the words, "the Spirit was not yet given," are to be applied to that giving accompanied with a visible sign which took place on the day of Pentecost.
Reply to Objection 2: The invisible mission takes place also as regards progress in virtue or increase of grace. Hence Augustine says (De Trin. iv, 20), that "the Son is sent to each one when He is known and perceived by anyone, so far as He can be known and perceived according to the capacity of the soul, whether journeying towards God, or united perfectly to Him." Such invisible mission, however, chiefly occurs as regards anyone's proficiency in the performance of a new act, or in the acquisition of a new state of grace; as, for example, the proficiency in reference to the gift of miracles or of prophecy, or in the fervor of charity leading a man to expose himself to the danger of martyrdom, or to renounce his possessions, or to undertake any arduous work.
Reply to Objection 3: The invisible mission is directed to the blessed at the very beginning of their beatitude. The invisible mission is made to them subsequently, not by "intensity" of grace, but by the further revelation of mysteries; which goes on till the day of judgment. Such an increase is by the "extension" of grace, because it extends to a greater number of objects. To Christ the invisible mission was sent at the first moment of His conception; but not afterwards, since from the beginning of His conception He was filled with all wisdom and grace.
Reply to Objection 4: Grace resides instrumentally in the sacraments of the New Law, as the form of a thing designed resides in the instruments of the art designing, according to a process flowing from the agent to the passive object. But mission is only spoken of as directed to its term. Hence the mission of the divine person is not sent to the sacraments, but to those who receive grace through the sacraments.
Whether it is fitting for the Holy Ghost to be sent visibly?
Objection 1: It would seem that the Holy Ghost is not fittingly sent in a visible manner. For the Son as visibly sent to the world is said to be less than the Father. But the Holy Ghost is never said to be less than the Father. Therefore the Holy Ghost is not fittingly sent in a visible manner.
Objection 2: Further, the visible mission takes place by way of union to a visible creature, as the Son's mission according to the flesh. But the Holy Ghost did not assume any visible creature; and hence it cannot be said that He exists otherwise in some creatures than in others, unless perhaps as in a sign, as He is also present in the sacraments, and in all the figures of the law. Thus the Holy Ghost is either not sent visibly at all, or His visible mission takes place in all these things.
Objection 3: Further, every visible creature is an effect showing forth the whole Trinity. Therefore the Holy Ghost is not sent by reason of those visible creatures more than any other person.